Insights into RC time curve fit analysis of pulmonary artery pressure decay.

The notion of a constant relationship between resistance and capacitance (RC time) in the pulmonary circulation has been challenged by more recent research. The RC time can be obtained using either a simplified empirical approach or a semilogarithmic equation. Although direct curve-fit analysis is a feasible and ostensibly reference approach for RC analysis, it remains largely unexplored. We aimed to study the relationship between various RC methods in different states of pulmonary hemodynamics. Methods In total, 182 patients underwent clinically indicated right heart catheterization. The pressure curves were exported and processed using the MATLAB software. We calculated the RC time using the empirical method (RCEST), semilogarithmic approach (RCSL), and direct measurement of curve fit (RCFIT). Results Among 182 patients, 137 had pulmonary hypertension due to left heart disease (PH-LHD), 35 had pulmonary arterial hypertension (PAH), and 10 demonstrated normal hemodynamics (non-PH). RCEST consistently overestimated the RCFIT and RCSL measurements by a mean of 75%. With all three methods, the RC values were longer in the PAH (RCFIT = 0.36 ± 0.14 s) than in the PH-LHD (0.27 ± 0.1 s) and non-PH (0.27 ± 0.09 s) groups (p < 0.001). Although the RCSL and RCFIT values were similar among the three subgroups, they exhibited broad limits of agreement. Finally, the RCEST demonstrated a strong discriminatory ability (AUC = 0.86, p < 0.001, CI = 0.79-0.93) in identifying PAH. Conclusion RC time in PAH patients was substantially prolonged compared to that in PH-LHD and non-PH patients. The use of the empirical formula yielded systematic RC overestimation. In contrast, the semilogarithmic analysis provided reliable RC estimates, particularly for group comparisons.

The Differential Impact of the Left Atrial Pressure Components on Pulmonary Arterial Compliance-Resistance Relationship in Heart Failure.

BACKGROUND: An increase in the pulmonary capillary wedge pressure (PAWP) has been shown to impact on the inherent relationship between the pulmonary arterial compliance (PAC) and pulmonary vascular resistance (PVR), thus augmenting the pulsatile relative to the resistive load of the right ventricle. However, the PAWP comprises the integration of both the steady and the pulsatile pressure components. We sought to address the differential impact of the these distinct PAWP components on the PAC-PVR relationship in a cohort of patients with heart failure. METHODS AND RESULTS: The study population consisted of 192 patients with hemodynamic findings diagnostic for heart failure. Off-line analysis was performed using the MATLAB software. The steady and pulsatile PAWP components were calculated as mid-A pressure and mean pressure during the V-wave oscillation, respectively. The PAC and PVR were hyperbolically and inversely associated and the subgroup of patients with PAWP above the median (>18 mm Hg) displayed a significant left and downward shift of the curve fit (P < .001). The shift in the PAC-PVR fit between patients with higher versus low steady PAWP was not significant (P = .43). In contrast, there was a significant downward and leftward shift of the PVR-PAC curve fit for the subgroup with a higher pulsatile PAWP (P < .001). Furthermore, only the pulsatile PAWP was significantly associated with the time-constant of the pulmonary circulation, assessed as the PAC × PVR product (P < .001). CONCLUSIONS: In patients with heart failure, the pulsatile rather than the steady PAWP component stands for the previously documented shift of the PAC-PVR relationship occurring at an elevated PAWP.

Feasibility and accuracy of tricuspid annular displacement assessed by speckle tracking echocardiography and Doppler tissue imaging.

BACKGROUND: Tricuspid annular plane systolic excursion (TAPSE) is a recommended quantitative measure of right ventricular (RV) longitudinal function assessed by M-mode echocardiography. Offline alternatives are desirable when TAPSE is unavailable. This study aimed to assess the feasibility, reliability, and agreement between retrospectively obtained measures of tricuspid annular displacement using Doppler tissue imaging (TADDTI ) and speckle tracking echocardiography (TADSTE ) compared with reference TAPSE. METHODS: Consecutive subjects referred for evaluation of heart failure were enrolled. Subjects in atrial fibrillation, significant valvular disease, or with poor image quality were excluded. TAPSE was measured during the examination using M-mode. TADSTE was measured as the maximal longitudinal displacement of the RV basal segment in systole using speckle strain imaging. TADDTI was derived offline from color-DTI superimposed grayscale images. RESULTS: 107 subjects (age 60 ± 16; 48% female) were analyzed. Both TADDTI and TADSTE demonstrated good feasibility and excellent intra- and inter-observer concordances. Although both measures demonstrated strong association with TAPSE, TADDTI showcased lower specificity to identify RV dysfunction and higher false positives. Bland-Altman analysis revealed a tendency of TADDTI to underestimate TAPSE (bias = 1.40; SD = 2.74 mm) as compared with TADSTE (bias = 0.27; SD = 2.30mm). Wide limits of agreement were observed for both methods. CONCLUSIONS: TADSTE and TADDTI provide reproducible and feasible quantification of RV function. However, TADDTI significantly underestimates TAPSE limiting the interchangeability of these modalities.

Heart rate and dyssynchrony in patients with cardiac resynchronization therapy: a pilot study.

OBJECTIVES: The objective of this pilot study was to describe the impact of paced heart rate on left ventricular (LV) mechanical dyssynchrony in synchronous compared to dyssynchronous pacing modes in patients with heart failure. METHODS: Echocardiography was performed in 14 cardiac resynchronization therapy (CRT) patients at paced heart rates of 70 and 90 bpm in synchronous- (CRT), and dyssynchronous (atrial pacing + wide QRS activation) pacing modes. LV dyssynchrony was quantified using the 12-segment standard deviation model (Ts-SD) derived from Tissue Doppler Imaging. In addition, cardiac cycle intervals were assessed using cardiac state diagrams and stroke volume (SV) and filling pressure were estimated. RESULTS: Ts-SD decreased significantly with CRT at 90 bpm (25 ± 12 ms) compared to 70 bpm (35 ± 15 ms, p = .01), but remained unchanged with atrial pacing at different paced heart rates (p = .96). The paced heart rate dependent reduction in Ts-SD was consistent when Ts-SD was indexed to average Ts and systolic time interval. Cardiac state diagram derived analysis of cardiac cycle intervals demonstrated a significant reduction of the pre-ejection interval and an increase in diastole with CRT compared to atrial pacing. SV was maintained at the higher paced heart rate with CRT pacing but decreased with atrial pacing. DISCUSSION: Due to the small sample size in this pilot study general and firm conclusions are difficult to render. However, the data suggest that pacing at higher heart rates acutely reduces remaining LV dyssynchrony during CRT, but not during atrial pacing with dyssynchronous ventricular activation. These results need confirmation in a larger patient cohort.

Three-dimensional dynamic morphology of the mitral valve in different forms of mitral valve prolapse - potential implications for annuloplasty ring selection.

BACKGROUND: Real-time three-dimensional transesophageal echocardiography has increased our understanding of the distinct pathomechanisms underlying functional, ischaemic or degenerative mitral regurgitation. However, potential differences in dynamic morphology between the subtypes of degenerative mitral prolapse have scarcely been investigated. METHODS: In order to compare the dynamic behavior of the different phenotypes of degenerative mitral valve prolapse, real-time three-dimensional transesophageal echocardiography recordings of 77 subjects, 27 with Barlow disease (BD), 32 with Fibroelastic deficiency (FED) and 18 normal controls (NC) were analysed. RESULTS: Geometric annular and valvular parameters of the myxomatous patients were significantly larger compared to controls (BD vs. FED vs. NC 3D annular area: 15 ± 2.8 vs. 13.3 ± 2.4 vs. 10.6 ± 2.3cm(2), all p < 0.01). Beside similar ellipticity, BD annuli were significantly flatter compared to FED. Myxomatous annuli appeared less dynamic than normals, with decreased overall 3D area change, however only the BD group differed from NC significantly (BD vs. FED vs. NC normalized 3D area change 4.40 vs. 6.81 vs. 9.69 %; BD vs. NC p = 0.000; FED vs. NC p = not significant, BD vs. FED p = 0.025). CONCLUSION: BD and FED differ not only in terms of valve morphology, but also annular dynamics. Both pathologies are characterized by annular dilatation. However, in BD the annulus is remarkably flattened and hypodynamic, whereas in FED its saddle-shape and contractile function is relatively preserved. These features might influence the choice of repair technique and the selection of annuloplasty ring.

Arterial-ventricular and interventricular interaction in isolated post-capillary and combined pulmonary hypertension in severe mitral stenosis.

BACKGROUND: Isolated post-capillary pulmonary hypertension (Ipc-PH) is characterized by elevated left atrial pressures that are passively transmitted upstream, whereas combined pre- and post-capillary PH (Cpc-PH) demonstrates additional reactive changes in pulmonary vasculature. The increased load imposed on the right ventricle (RV) influences left ventricular (LV) mechanics by means of interventricular interaction. However, there is lack of evidence to substantiate the effect of possible additional alterations in the arterio-ventricular (AV) coupling and their effect on LV function. Considering the discrepant RV load in Cpc-PH and Ipc-PH, we sought to investigate whether these two conditions are also characterized by differential alterations in AV coupling. METHODS AND RESULTS: Invasive hemodynamic and echocardiographic data of 120 patients with PH due to severe rheumatic mitral stenosis before and immediately after percutaneous valvulotomy, along with 40 age-matched healthy controls, were analyzed. Effective arterial (E a) and ventricular elastance (E es) were measured. PH patients demonstrated elevated LV afterload (E a) along with AV uncoupling, and these derangements were more evident in the Cpc-PH group [E a: 3.3 (2.3-5.4) vs 2.6 (2.1-3.5) mmHg/mL, E a/E es: 0.73 (0.6-0.9) vs 0.88 (0.7-1.2), p < 0.05]. In addition, PH was associated with reduced LV deformation, which was mainly determined by elevated E a, while the effect of interventricular interaction was limited to the septal wall. CONCLUSIONS: Our results suggest that in addition to the interventricular interaction, an abnormal AV coupling contributes to the altered LV mechanics that has been associated with adverse prognosis in Cpc-PH.

Increases in Cardiac Output and Oxygen Consumption During Enhanced External Counterpulsation.

BACKGROUND: Regular enhanced external counterpulsation (EECP) improves exercise capacity possibly through a training effect, but the roles of oxygen consumption (VO2) vs. direct EECP effects (diastolic augmentation, DA-ratio), and their relation to cardiac index (CI) during EECP are unknown. METHODS: We studied eight patients with angina pectoris (median [range] age 72 [53-85], 25% women), who underwent EECP for 35 daily sessions. Before, during and after the first and last sessions, we assessed VO2, DA-ratio and CI. RESULTS: At first EECP, CI increased from 2.2 (1.7-2.9) L/min/m2 prior to EECP to 3.0 (2.2-3.8) during EECP (p=0.011), and returned to 2.4 (0.8-3.0). Similarly, VO2 increased during EECP and returned to baseline after EECP. These patterns were reproduced at the last EECP session. Absolute values of CI and VO2 correlated with each other during but not prior to or after EECP. The increase in CI correlated with the increase in VO2 by trend: (first session, r 0.52, p=0.19; second session r 0.69, p=0.09), but not with DA-ratio. CONCLUSIONS: Acutely during EECP, there is an increase in cardiac output that is unrelated to direct EECP effects but related to, and may be secondary to, an increase in peripheral O2 demand. This may represent a training effect.

The impact of arterial load on left ventricular performance: an invasive haemodynamic study in severe mitral stenosis.

KEY POINTS: A hallmark of mitral stenosis (MS) is the markedly altered left ventricular (LV) loading. As most of the methods used to determine LV performance in MS patients are influenced by loading conditions, previous studies have shown conflicting results. The present study calculated LV elastance, which is a robust method to quantify LV function. We demonstrate that LV loading in MS patients is elevated but normalizes after valve repair and might be a result of reflex pathways. Additionally, we show that the LV in MS is less compliant than normal due to a combination of right ventricular loading and the valvular disease itself. Immediately after valve dilatation the increase in blood inflow into the LV results in even greater LV stiffness. Our findings enrich our understanding of heart function in MS patients and provide a simple reproducible way of assessing LV performance in MS. ABSTRACT: Left ventricular (LV) function in rheumatic mitral stenosis (MS) remains an issue of controversy, due to load dependency of previously employed assessment methods. We investigated LV performance in MS employing relatively load-independent indices robust to the altered loading state. We studied 106 subjects (32 ± 8 years, 72% female) with severe MS (0.8 ± 0.2 cm(2) ) and 40 age-matched controls. MS subjects underwent simultaneous bi-ventricular catheterization and transthoracic echocardiography (TTE) before and immediately after percutaneous transvenous mitral commisurotomy (PTMC). Sphygmomanometric brachial artery pressures and TTE recordings were simultaneously acquired in controls. Single-beat LV elastance (Ees ) was employed for LV contractility measurements. Effective arterial elastance (Ea ) and LV diastolic stiffness were measured. MS patients demonstrated significantly elevated afterload (Ea : 3.0 ± 1.3 vs. 1.5 ± 0.3 mmHg ml(-1) ; P < 0.001) and LV contractility (Ees : 4.1 ± 1.6 vs. 2.4 ± 0.5 mmHg ml(-1) ; P < 0.001) as compared to controls, with higher Ea in subjects with smaller mitral valve area (≤ 0.8 cm(2) ) and pronounced subvalvular fusion. Stroke volume (49 ± 16 to 57 ± 17 ml; P < 0.001) and indexed LV end-diastolic volume (LVEDVindex : 57 ± 16 to 64 ± 16 ml m(-2) ; P < 0.001) increased following PTMC while Ees and Ea returned to more normal levels. Elevated LV stiffness was demonstrated at baseline and increased further following PTMC. Our findings provide evidence of elevated LV contractility, increased arterial load and increased diastolic stiffness in severe MS. Following PTMC, both LV contractility and afterload tend to normalize.

Right ventricular wave reflection relate to clinical measures in pulmonary arterial hypertension.

OBJECTIVES: When a forward running pressure wave from the right ventricle reaches the narrow vessels in the pulmonary circulation, it is reflected as a backward running wave. We aimed to relate changes in right ventricular waveform reflection (RVWR) to changes in clinical variables in pulmonary arterial hypertension (PAH) patients. DESIGN: Twenty-one PAH patients with RV waveform recordings from two sequential catheterisations at least 6 months apart were included. Six-minute walked distance (6MWD) and brain natriuretic peptide (BNP) level were also available. RVWR was defined as 'the pressure from the inflection point on the upstroke RV pressure wave to RV peak pressure'. Direction of change in RVWR, 6MWD and BNP was classified as (+) if increased and (-) if decreased. Spearman correlations were used to analyse the relation between changes. Pearson's correlation coefficient was used to analyse relation between RVWR and pulmonary vascular resistance (PVR). RESULTS: The correlation between change in RVWR and 6MWD was - 0.67 (p < 0.01) and between RVWR and BNP was - 0.53 (p < 0.05). Actual RVWR and PVR correlated both at first (0.56, p < 0.001) and at second right heart catheterisation (0.45, p < 0.001). CONCLUSION: RVWR might have clinical implications indicating a change in clinical status and disease progression in patients with PAH.

The pulmonary capillary wedge pressure accurately reflects both normal and elevated left atrial pressure.

BACKGROUND: Pulmonary capillary wedge pressure (PCWP) is routinely used as an indirect measure of the left atrial pressure (LAP), although the accuracy of this estimate, especially under pathological hemodynamic conditions, remains controversial. OBJECTIVES: The aim of this prospective study was to investigate the reliability of PCWP for the evaluation of LAP under different hemodynamic conditions. METHODS: Simultaneous left and right heart catheterization data of 117 patients with pure mitral stenosis, obtained before and immediately after percutaneous mitral comissurotomy, were analyzed. RESULTS: A strong correlation and agreement between PCWP and LAP measurements was demonstrated (correlation coefficient = 0.97, mean bias ± CI, 0.3 ± -3.7 to 4.2 mm Hg). Comparison of measurements performed within a 5-minute interval and those performed simultaneously revealed that simultaneous pressure acquisition yielded better agreement between the 2 methods (bias ± CI, 1.82 ± 1.98 mm Hg). In contrast to previous observations, the discrepancy between the 2 measures did not increase with elevated PCWP. Multiple regression analysis failed to identify hemodynamic confounders of the discrepancy between the 2 pressures. The ability of PCWP to distinguish between normal and elevated LAP (cutoff set at 12 and 15 mm Hg, respectively), as tested by receiver operating characteristics analysis, demonstrated a remarkably high diagnostic accuracy (area under the curve: 0.989 and 0.996, respectively). CONCLUSIONS: Although the described limits of agreement may not allow the interchangeability of PCWP and LAP, especially at lower pressure ranges, our data support the clinical use of PCWP as a robust and accurate estimate of LAP.

Echocardiographic estimation of pulmonary artery wedge pressure: invasive derivation, validation, and prognostic association beyond diastolic dysfunction grading.

AIMS: Grading of diastolic function can be useful, but indeterminate classifications are common. We aimed to invasively derive and validate a quantitative echocardiographic estimation of pulmonary artery wedge pressure (PAWP) and to compare its prognostic performance to diastolic dysfunction grading. METHODS AND RESULTS: Echocardiographic measures were used to derive an estimated PAWP (ePAWP) using multivariable linear regression in patients undergoing right heart catheterization (RHC). Prognostic associations were analysed in the National Echocardiography Database of Australia (NEDA). In patients who had undergone both RHC and echocardiography within 2 h (n = 90), ePAWP was derived using left atrial volume index, mitral peak early velocity (E), and pulmonary vein systolic velocity (S). In a separate external validation cohort (n = 53, simultaneous echocardiography and RHC), ePAWP showed good agreement with invasive PAWP (mean ± standard deviation difference 0.5 ± 5.0 mmHg) and good diagnostic accuracy for estimating PAWP >15 mmHg [area under the curve (95% confidence interval) 0.94 (0.88-1.00)]. Among patients in NEDA [n = 38,856, median (interquartile range) follow-up 4.8 (2.3-8.0) years, 2756 cardiovascular deaths], ePAWP was associated with cardiovascular death even after adjustment for age, sex, and diastolic dysfunction grading [hazard ratio (HR) 1.08 (1.07-1.09) per mmHg] and provided incremental prognostic information to diastolic dysfunction grading (improved C-statistic from 0.65 to 0.68, P < 0.001). Increased ePAWP was associated with worse prognosis across all grades of diastolic function [HR normal, 1.07 (1.06-1.09); indeterminate, 1.08 (1.07-1.09); abnormal, 1.08 (1.07-1.09), P < 0.001 for all]. CONCLUSION: Echocardiographic ePAWP is an easily acquired continuous variable with good accuracy that associates with prognosis beyond diastolic dysfunction grading.

Impact of tachycardia and sympathetic stimulation by cold pressor test on cardiac diastology and arterial function in elderly females.

Abnormal vascular-ventricular coupling has been suggested to contribute to heart failure with preserved ejection fraction in elderly females. Failure to increase stroke volume (SV) during exercise occurs in parallel with dynamic changes in arterial physiology leading to increased afterload. Such adverse vascular reactivity during stress may reflect either sympathoexcitation or be due to tachycardia. We hypothesized that afterload elevation induces SV failure by transiently attenuating left ventricular relaxation, a phenomenon described in animal research. The respective roles of tachycardia and sympathoexcitation were investigated in n = 28 elderly females (70 ± 4 yr) carrying permanent pacemakers. At rest, during atrial tachycardia pacing (ATP; 100 min(-1)) and during cold pressor test (hand immersed in ice water), we performed Doppler echocardiography (maximal untwist rate analyzed by speckle tracking imaging of rotational mechanics) and arterial tonometry (arterial stiffness estimated as augmentation index). Estimation of arterial compliance was based on an exponential relationship between arterial pressure and volume. We found that ATP produced central hypovolemia and a reduction in SV which was larger in patients with stiffer arteries (higher augmentation index). There was an associated adverse response of arterial compliance and vascular resistance during ATP and cold pressor test, causing an overall increase in afterload, but nonetheless enhanced maximal rate of untwist and no evidence of afterload-dependent failure of relaxation. In conclusion, tachycardia and cold provocation in elderly females produces greater vascular reactivity and SV failure in the presence of arterial stiffening, but SV failure does not arise secondary to afterload-dependent attenuation of relaxation.

Transesophageal echocardiography measurements of aortic annulus diameter using biplane mode in patients undergoing transcatheter aortic valve implantation.

BACKGROUND: Aortic stenosis (AS) is a relevant common valve disorder. Severe AS and symptoms and/or left ventricular dysfunction (EF <50%) have the indication for aortic valve replacement (AVR). Majority of the patients with AS are elderly often with co-morbidities and generally have high preoperative risk. Transcatheter aortic valve implantation (TAVI) is offered in this group. Four different sizes of Corevalve prosthesis are available. Correct measurement of aortic size prior to TAVI is of great important to choose the right prosthesis size to avoid among others paravalvular leak or prosthesis patient mismatch.Aim of the study is to assess the aortic annulus diameter in patients undergoing TAVI by biplane (BP) mode using transesophageal echocardiography (TEE) and compare it to two-dimensional (2D) transthoracic echocardiography (TTE) and 2DTEE using three-dimensional (3D) TEE as reference method. METHODS: The study population consisted of 50 patients retrospectively (24 men and 26 women, mean age 85±8 years of age) who all had undergone echocardiography examination prior to TAVI. RESULTS: The mean aortic annulus diameter was 20.4±2.2 mm with TTE, 22.3±2.5 mm with 2DTEE, 22.9±1.9 mm with BP-mode and 23.1±1.9 mm with 3DTEE. TTE underestimated the mean aortic annulus diameter in comparison to transesophageal imaging modalities (p<0.001). Using 3DTEE, 2% of patients were unsuitable for TAVI due to a too-small AoA (n=1). This figure was similar with BP (4%, n=2; p=1.00) but considerably larger with 2DTTE (36%, n=18; p < 0.001) and 2DTEE (12%, n=6; p=0.06). There was a strong correlation between BP-mode and 3DTEE for assessment of aortic annulus diameter (r-value 0.88) with small mean difference (-0.2±0.9 mm) whereas the other modalities showed larger 95% confidence interval and modest correlation (2DTTE vs. 3DTEE, -6.3 to 0.9 mm, r=0.64 and 2DTEE vs. 3DTEE, -4.8 to 3.2 mm, r=0.61). CONCLUSION: A multi-dimensional method is preferred to assess aortic annulus diameter in TAVI patients since there is risk of underestimation using single plane. Biplane mode is the method of choice in view of speedy post-processing with no need for expensive dedicated software. Lastly, single plane methods lead to misclassification of patients as unsuitable for TAVI. This may be of major clinical importance.

BASILICA Procedure Prior to Valve-in-Valve TAVR in a Supra-Annular TAV Prosthesis.

An 80-year-old man with a supra-annular transcatheter aortic valve (TAV) prosthesis presented with severe transvalvular aortic regurgitation 18 months after the TAV replacement procedure. The authors report the first ever valve-in-valve procedure using BASILICA (bioprosthetic or native aortic scallop intentional laceration to prevent iatrogenic coronary artery obstruction) in such a supra-annular TAV prosthesis. Minimal paravalvular leakage, normal coronary artery flow, and easy coronary access were seen postimplantation. (Level of Difficulty: Advanced.).

Longitudinal strain analysis for assessment of early cardiotoxicity during anthracycline treatment in childhood sarcoma: A single center experience.

BACKGROUND: The growing population of long-term childhood cancer survivors encounter a substantial burden of cardiovascular complications. The highest risk of cardiovascular complications is associated with exposure to anthracyclines and chest radiation. Longitudinal cardiovascular surveillance is recommended for childhood cancer patients; however, the optimal methods and timing are yet to be elucidated. AIMS: We aimed to investigate the feasibility of different echocardiographic methods to evaluate left ventricular systolic function in retrospective datasets, including left ventricular ejection fraction (LVEF), fractional shortening (FS), global longitudinal strain (GLS) and longitudinal strain (LS) as well as the incidence and timing of subclinical left ventricular dysfunction detected by these methods. METHODS AND RESULTS: A retrospective longitudinal study was performed with re-analysis of longitudinal echocardiographic data, acquired during treatment and early follow-up, including 41 pediatric sarcoma patients, aged 2.1-17.8 years at diagnosis, treated at Astrid Lindgren Children's Hospital, Stockholm, Sweden, during the period 2010-2021. All patients had received treatment according to protocols including high cumulative doxorubicin equivalent doses (≥250 mg/m2 ). In 68% of all 366 echocardiograms, LS analysis was feasible. Impaired LS values (<17%) was demonstrated in >40%, with concomitant impairment of either LVEF or FS in 20% and combined impairment of both LVEF and FS in <10%. Importantly, there were no cases of abnormal LVEF and FS without concomitant LS impairment. CONCLUSION: Our findings demonstrate feasibility of LS in a majority of echocardiograms and a high incidence of impaired LS during anthracycline treatment for childhood sarcoma. We propose inclusion of LS in pediatric echocardiographic surveillance protocols.

Altered ventriculo-arterial coupling during exercise in athletes releasing biomarkers after endurance running.

Exercise can lead to release of biomarkers such as cardiac troponin T (cTnT) and N-terminal pro-brain natriuretic peptide (NT-proBNP), a poorly understood phenomenon proposed to especially occur with high-intensity exercise in less trained subjects. We hypothesised that haemodynamic perturbations during exercise are larger in athletes with cTnT release, and studied athletes with detectable cTnT levels after an endurance event (HIGH; n = 16; 46 ± 9 years) against matched controls whose levels were undetectable (LOW; n = 11; 44 ± 7 years). Echocardiography was performed at rest and at peak supine bicycle exercise stress. Left ventricular (LV) end-systolic elastance (E (LV) a load-independent measure of LV contractility), effective arterial elastance (E (A) a lumped index of arterial load) and end-systolic meridional wall stress were calculated from cardiac dimensions and brachial blood pressure. Efficiency of cardiac work was judged from the ventriculo-arterial coupling ratio (E (A)/E (LV): optimal range 0.5-1.0). While subgroups had similar values at rest, we found ventriculo-arterial mismatch during exercise in HIGH subjects [0.47 (0.39-0.58) vs. LOW: 0.73 (0.62-0.83); p < 0.01] due to unopposed increase in E (LV) (p < 0.05). In LOW subjects, a greater increase occurred in E (A) during exercise (+81 ± 67 % vs. HIGH: +39 ± 32 %; p = 0.02) which contributed to a maintained coupling ratio. Subjects with higher baseline NT-proBNP had greater systolic wall stress during exercise (R (2) = 0.39; p < 0.01) despite no correlation at rest (p = ns). In conclusion, athletes with exercise-induced biomarker release exhibit ventriculo-arterial mismatch during exercise, suggesting non-optimal cardiac work may contribute to this phenomenon.

Sex differences in response to maximal exercise stress test in trained adolescents.

BACKGROUND: Sex comparisons between girls and boys in response to exercise in trained adolescents are missing and we investigated similarities and differences as a basis for clinical interpretation and guidance. METHODS: A total of 24 adolescent females and 27 adolescent males aged 13-19 years underwent a maximal bicycle exercise stress test with measurement of cardiovascular variables, cardiac output, lung volumes, metabolic factors/lactate concentrations and breath-by-breath monitoring of ventilation, and determination of peak VO(2). RESULTS: Maximum heart rate was similar in females (191 ± 9 bpm) and males (194 ± 7 bpm), cardiac index at maximum exercise was lower in females (7.0 ± 1.0 l/min/m(2)) than in males (8.3 ± 1.4 l/min/m(2), P < 0.05). Metabolic responses and RQ at maximum exercise were similar (females: 1.04 ± 0.06 vs. males: 1.05 ± 0.05). Peak VO(2) was lower in females (2.37 ± 0.34 l/min) than in males (3.38 ± 0.49 l/min, P < 0.05). When peak VO(2) was normalized to leg muscle mass sex differences disappeared (females: 161 ± 21 ml/min/kg vs. males: 170 ± 23 ml/min/kg). The increase in cardiac index during exercise is the key factor responsible for the greater peak VO(2) in adolescent boys compared to girls. CONCLUSIONS: Differences in peak VO(2) in adolescent boys and girls disappear when peak VO(2) is normalized to estimated leg muscle mass and therefore provide a tool to conduct individual and intersex comparisons of fitness when evaluating adolescent athletes in aerobic sports.

Two-dimensional color Doppler echocardiography for left ventricular stroke volume assessment: a comparison study with three-dimensional echocardiography.

AIM: Whether measurement of left ventricular outflow tract diameter (LVOTd) using color Doppler (CD) in order to more accurately define LVOTd is more accurate for determination of stroke volume (SV) than gray scale and compare it with direct measurement of LVOT area (a) using three-dimensional echocardiography (3DE) for SV determination. METHODS AND RESULTS: Twenty-one volunteers were examined. LVOTa was calculated by two-dimensional echocardiography (2DE) using the following formula: π× (d/2)(2) , d = LVOT diameter by gray scale and CD, respectively. Planimetry of LVOTa was performed in parasternal long axis using 3DE. Eccentricity Index was calculated using the lateral and anterior-posterior LVOTd. SV was obtained by four different methods: (1) 2D gray scale, (2) 2D color, (3) LVOTa × LVOT velocity time integral, and (4) SV by Simpson's biplane method. Gray scale LVOTd was significantly smaller compared to LVOTd obtained with CD (P < 0.05). Significant differences occurred between LVOTa gray scale and CD (3.29 ± 0.74 cm(2) vs 3.67 ± 0.70 cm(2) , P < 0.05) and between LVOTa calculated by gray scale in comparison to 3DE planimetry; (3.29 ± 0.74 cm(2) vs 3.61 ± 0.89 cm(2) , P = 0.011). Half of the subjects had at least 17% difference between the lateral and anterior-posterior LVOTd. There were significant differences between SV by 2D gray scale and 2D CD (82.8 ± 17.1 mL vs 92.4 ± 16.8 mL, P < 0.05) and between 2D gray scale and 3DE planimetry (82.8 ± 17.1 mL vs 90.7 ± 19.8 mL, P = 0.025). CONCLUSION: Our study demonstrates LVOT being frequently elliptical. SV and LVOTa were found to be similar when comparing 2DE CD and 3DE planimetry and showed higher values in comparison to 2DE gray scale, which suggests 2DE CD to be an alternative approach for SV assessment.